In 2017, researchers pointed to NASA's Spitzer Space Telescope against the known object
– The first known interstellar object to visit our solar system. Infrared
Spitzer was one of many telescopes pointing to "Oumuamua in the weeks after that
discovered that October.
too weak for Spitzer to detect when it looked more than two months later
The object's closest to the ground in early September. But "non-discovery"
sets a new limit to how much the strange object can be. The results are
reported in a new study published today in the Astronomical Journal and
coauthored by scientists at NASA's Jet Propulsion Laboratory in Pasadena,
Researchers have concluded that ventilation on the surface of "Oumuamua must have released gas jets, giving the object a slight increase in speed, which researchers discovered by measuring the position of the object as it passed by the Earth in 2017. Credit: NASA / JPL -Caltech
The new size limit
is in line with the results of a research paper published earlier
this year, which suggested that gasification was responsible
Small changes in "Oumuamuas speed and direction as tracked last year:
The authors of this document find that the expelled gas acted as a small propeller
gently press the object. That determination was dependent on "Oumuamuas creature
relatively less than common solar system comets. (Conclusion that
"Oumuamua's experienced gasification suggested it was composed of frozen gases,
resembles a comet.)
"& # 39; Oumuamua
have been full of surprises from day one so we were eager to see what Spitzer could do
show, "says David Trilling, senior author of the new study and a professor
of astronomy at Northern Arizona University. "The fact that" Oumuamua was
Too small for Spitzer to detect is actually a very valuable result. "
first discovery of the University of Hawaii Pan-STARRS 1 telescope on
Haleakala, Hawaii (The object's name is a Hawaiian word meaning "visitor"
from remote arrival first "), in October 2017 while the telescope was
measurement for near asteroids near the earth.
observations made by several terrestrial telescopes and NASA's Hubble
The space telescope discovered the sunlight reflected by the Oumuamuas surface. Great
variations in object brightness suggested that "oumuamua is very elongated
and probably less than half a mile (2,600 feet, or 800 meters) in its longest
traces asteroids and comets using infrared energy, or heat that they radiate,
which can provide more specific information about an object's size than optical
observations of reflected sunlight alone should.
The fact that
"Oumuamua was too weak for Spitzer to discover setting a limit on the total of the object
surface area. Since non-detection can not be used to assume form,
Size limits are presented as "Oumuamuas diameter would be if it were
spherical. Use three separate models that make slightly different assumptions
about the composition of the object, Spitzer's non-detection-restricted "Oumuamuas" spherical
diameter "to 1,440 feet (440 meters), 460 feet (140 meters) or maybe like
a bit like 320 meters (100 meters). The wide range of results derives from
assumptions about "Oumuamuas composition, which affects how visible (or weak)
It seems that Spitzer was a certain size.
Small but reflective
The new study
also suggests that "Oumuamua can be up to 10 times more reflective than comet
who lives in our solar system – a surprising result, according to the paper
Author. Since infrared light is largely the heat radiation produced by
"hot" object, it can be used to determine the temperature of a
comet or asteroid; In turn, this can be used to determine the reflectivity of
The subject area – what researchers call Albedo. Just like a dark t-shirt in sunlight
Heats up faster than a light, retaining an object with low reflectivity
more heat than an object with high reflectivity. So a lower temperature means a
A comet s
Albedo can change throughout its lifetime. When it passes near the sun, a
The comets heat up and turn directly into a gas, soaking dust and dirt
the surface of the coma and reveals more reflective ice.
has traveled through interstellar space for millions of years far from anyone
star that can update its surface. But it may have gotten its surface updated
such "outgassing" when it made an extremely close approach for our Sun,
little more than five weeks before it was discovered. In addition to sweeping
remove dust and dirt, some of the released gas may have covered the surface of
& # 39; Oumuamua with a reflective rock of ice and snow – a phenomenon as well
observed in comets in our solar system.
on our way out of our solar system – almost as far from the sun as Saturn
track – and far beyond reach of existing telescopes.
If we get a measurement from a comet that's so weird, we'll go back and
measure it again until we understand what we see, says david
Farnocchia, from the Center for Near Earth Object Studies (CNEOS) at JPL and a
co-authors on both sides. "But this one is gone forever, we probably know
as much about what we will ever know. "
JPL manages the Spitzer Space Telescope mission for NASA
Science Mission Directorate in Washington. Science activities are conducted
Spitzer Science Center at Caltech, Pasadena, California. Spaceship
The operations are based on Lockheed Martin Space Systems Company in Littleton,
Colorado. Data archived at Infrared Science Archive hosted by IPAC on
Caltech. Caltech manages JPL for NASA.
For more information about Spitzer visit:
News Media Contact
Jet Propulsion Laboratory, Pasadena, California.